The actual falls is about a 15 minute hike. You could hike more and get more waterfalls, but given how cold it was, we retreated back to the car to head towards Myvatn Nature Baths. I don't actually have any pictures of the baths, but Bowen and I both enjoyed it. It's quieter than the Blue Lagoon, but also has a much stronger smell. I wouldn't recommend a trip just to visit it, but if you're in the area it's not a bad place despite the exceedingly expensive restaurant on-site.
At Akureyri, we found our AirBnB near downtown. I'd booked the place thinking that it would be a great place to explore the town, but in reality, the town was really tiny! We did manage to walk downtown to eat at a restaurant, and it was also nice that the nearest supermarket was within walking distance, but the town itself wasn't nearly as pretty as the environs.